Torque loading lash adjusting de



July 19, 1938. w. n. GovE ET AL TORQUE LOADING LASH ADJUSTI'NG DEVICE lFOR FRICTION ROLLER TRANSMISSIONS 2 Sheets-Shut 1 @a Lm w Q au@ dw uw ,n Su li l.: ad NQ www. QN. Q H\ mm. w QQ H\ Q s@ Q Rw .l Q H l |m www 9.1 E up @m Sw WN NN ,L N@ H M Mm. @NWN NR Q w l S Sww eww Q w uw w w QN QN f July 19, 1938. w. D. GovE ET AL Re. 20,801

TORQUE LOADING LASH ADJUSTING DVICE FDR FRICTION ROLLER TRANSMISSIONS original Filed may s1, 1954 '2 shets-sheet 2 www 'fria/d @juz/e f .91711 l y & fz .@0224 j Reissued July 19, 1'938V TOR`QUELOADIG LASH ADJUSTING DE- VICE FOR FRICTION RLLEB TRANSMIS- SIONS v Winfield D. Gove, East Hartford; Conn., and John Dolza, Flint, Mich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware l Original No. 2,030,203, February 11,- 193B,

Serial No. 728,264, May 31, 1934.

Application for reissue August 10, 1936, Serial No. 95,094

l 6 Claims.

T his invention relates to friction race-and-roller transmission mechanisms, and particularly to means for squeezing the rollers between the races with a force which varies with the torque transmitted. Means functioning to this end, in friction race-and-roller transmission mechanisms for motor vehicles, have been commonly referred to astorque loading devices and may conveniently consist oi cams and interposed rolling bodies.

Troubles havebeen experienced, in automobile transmissions of the aforesaid type, equipped with torque loading devices, by looseness between the elements of the torque loading devices occurring as a result oi wmadeformation of transmission elements, or variations of axial distance between race surfaces however caused. Ii looseness occurs in the torque loading devices there results, obviously, a looseness in the driving train between engine and vehicle wheels. a loss of axial pressure oi races on rollers, and possible failure to transmit the torque required.

It is lan objectV of this invention to take up automatically any looseness occurring in the torque loading devices of a race and roller transmission mechanism whatever the cause.

Said object is achieved by means of an adjustable gag arranged to back up one cam or equivaient element of the torque loading device, in combination with a spring exerting a constant elastic force on the gag in a direction to move it so as to take up any slack that may occur in the torque loading elements. This adjustment occurs, of course, only at those periods when no torque is 'being transmitted by the torque loadciated with -a torque loading .device embodying this invention;

Fig. 2 is a transverse section through the torque loading rollers taken on a plane indicated by line 2 2, Fig. 1;

Fig. 3 is a fragmentary longitudinal section on a plane indicated by line 3 3 oi Fig. 2;

Fig. 4 is a view from beneath. partly in section.

an automatic take-up device for maintaining the cooperating elements -of the torque loading device in close contact, and

Fig. 5 is a diagram showing in section a pair of races including that one which is actedon directly by the torque loading device.

In Fig. 1 there is shown one form of race-androller transmission mechanism associated with means embodying this invention, for axially pressing the races toward one another and squeezing the rollers between them. The transmission mechanism illustrated is or the duplex race and roller type consisting of two sets oi coaxial toroidal races and corresponding sets voi? interposed rollers whereby the power communicated to the driving races by the input shaft is transmitted in parallel by the two sets of rollers and two drivenA races to the output shaft. Referring to the details of construction illustrated in Fig; 1, numeral i0 indicates a transmission. casing. Ar supporting and strengthening structure, comprising parallel members i2 and |24 joined by a parti-cylindrical web Il, is fitted within and pinned to the casing i0. This structure may consist o! an'integral casting. Members I2 and lzahave alined central holes in which a frame tube I6 is snugly fitted. A colla'r i811., welded or otherwise bonded to tube I6 is secured also as by bolts 2li to member IIa. Collar IBa serves also as a stop cooperating with stops on the roller carriers of one set to limit tilting of the rollers to low ratio position. A collarv iB serves also as a stop to similarly limit the tilting oi the rollers of the other set. Members i2 and Ila also have a plurality oi equally spaced openings to accommodate the several intermediate rollers of each set.

A hub-like `tubular member 22 is rdtatabiy mounted on frame tube I8 between members i2 and lia. Gear 24 is secured centrally to member 22 and driving races 26, 28a, are sleeved over the end portions oi member 22 that protrude from gear 24, and are free to rotate thereon. A number o! rollers, one oi' which is shown at 28 (Fig. 1) seated in slots through gear 24. and capable of rotating about radial axes. have their peripheries in contact with the backs of toroidal driving races 26, 26a. Rollers 28 constitute diierential driving means between gear 2l and races 26, 26a. Gear 24' meshes with a driving gear 28a adapted y at one end by universal Joints 43, 43a, to the supporting members |2 and I2a.

Control means effective on the carriers 42 and 42a, actuated by external influences, adJusts the rollersv to desired different ratio positions. Portions of the control mechanism are shown i n Fig. l, in the angularly movable collars 44, 44a, adapted to be rocked by control links 46 and 46a, and in the links 49, 40a, the outer ends of which are universally pivoted to the carriers at 50 and 50a.

Stops 52, 52a, on the carriers cooperate with the stop collars I8.' and Ia to limit the tilt of rollers 40, 40a, toward low ratio position when output shaft 34 is rotated in reverse.

Drivenrace 32 is keyed to output shaft 34 and abutment 54. Driven race 32a is axially movable on shaft34 and is capable of a limited rotation thereon as permitted by the torque loading de' vices bearing against its back, to be described.

Driving races 26 and 26a are capable of some axial movement with respect to output shaft and the driven races. Carriers 42 and 42a, being attached to the frame members I2, |2a, only by universal joints at one end, the rollers being mounted at their free ends, permit, of course, slight movement of the roller centers should the races be moved closer together.

The construction thus far described is exemplary of a race and roller transmission mecha-l nism to which the torque loading device. of this invention is applicable. 'I'he transmission mechanism itself is not a part of the invention claimed herein.

The torque loading means, for squeezing the :l races and rollers together with the force necessary to enable them to transmit the torque required under varying loads is shown in section at the right of Fig. 1. In Fig. l, outputshaft 34 is shown grooved or splined at 60, slightly reduced and threaded at `62, at the right of the splined portion, and still further reduced at the cylindrical end portion 04. An adjustable abutment collar 66 (see also Fig. 4) is shown sleeved over the reduced end 94 of shaft 34. Reduced portion 64 is axially drilled and tapped to receive adjusting bolt 68, the lar'ge head of which bears against the rear of abutment 86. The bolt can be locked -against laccidental rotation by a bolt lock 69;

A sleeve 10 surrounds the torque loading elements and its rear endY extends over adjustable abutment E.

between which, and abutment 90, is a row of bearing balls 16. 'I'he other orforward end of sleeve fore, bep'seen that the races and rollers may be pressed together elastically by the 'action of Ispring 9,0, and vthat the degreeA of 'elastic loading may be varied by turning the bolt 68. The elastic An annular` shoulder 12 within the sleeve 10 forms a seat for a bearing race 14,

on the splined part 60 of shaft 34, rollers 94 interposed between the cams on race 32a and member 92, cage 96, for retaining rollers 94, adjustable abutment member or take-up gag, in the form of nut 99, threaded at B2. on shaft 24 and bearing against the rear of slidable member 92, and spiral automatic take-up' spring |00. The nut 99 acts as a positive take-up of all slack or lost motion between member` 92 of the torque loading assembly and the threads 92 on the shaft 34, said threads serving as abutment means which resists the reaction force of the torque loading means through the gag nut 99. Spring 00 has one bent lend |02 (Flg.4) seated in one of the axial grooves |04 in the periphery of threaded nut 90, and the other end |09 turned toward the spring axis and inserted in a groove |00 in the reduced extremity 64 of shaft 34. Spring |00 may be biased or pretensioned any desired extent before seating the ends in both the prepared grooves. The nut 99 may be rotated until cams and rollers are in firm contact, with the rollers seated in the lowest parts or centers of the cam surfaces, and after that the spring having` one end locked in groove |08 of shaft 34, may be placed under tension and its end |02 inserted in the appropriate groove |04 of the adjusting nut, so that its elastic force is exerted in a direction to screw up the nut in case any looseness thereafter should occur between the cams and rollers ofthe torque loading elements.

It will be apparent that the nut 98 biased by spring |00 in a direction to take up any slack between the cams and rollers of the torque loading,device and restore to that device capacity to impart the greatest amplitude of axial movement for which it was designed, acts as a wedging gag between the threads at 92 on shaft 24 and the rear end of element 92.

Although a take-up or gag in the form of a nut 98 and a spiral biasing spring |00 are illustrated and described, it Isunderstood that the desired result may be achieved by other forms of gags and biasing means within the scope of this invention.

'There is a measurable deflection evidenced in an axial direction in race and roller transmission mechanisms. due to the elastic deformation of races, rollers, and other elements when subjected to the axial force exerted bythe loading means squeezing the rollers between the races. The extent of elastic deflections or yield in an axial direction of all of theV elastic elements of a gear position, and that the least axial deflection occurs when the rollers are parallel with the way of the driven race 32a, in an axial plane,

race axis or substantially in 1:1 ratio position. It will be understood, however, that the extent of elastic yield must vary with different designs, different proportionsy of races and rollers and different materials. f

In some race and roller transmission mechanisms the elastic yield or deflection in an axial direction may be greatest when the rollers are` .ing in parallel therewith, the torque loading elements, if automatically adjusted'to take up all slack when the transmission elements are in position of greatest axial elastic deection, cannot back od, as it were, when the transmission elements are in position of least or lesser axial deflection, and therefore the transmission becomes loaded too heavily by the torque loading means. The conditions mentioned would occur if the curvature of the driving and driven raceways in an axial plane had the saine center of curvature and the same radius of curvature, as is customary in toric race and roller transmission mechanism.

In order to avoid overloading the races and rollers undei the described conditions owing to the inability of the automatic take-up torque loadling device to slacken, retreat, or fback-up from any advanced adjustment imparted by the spring to the gag element 9B, in a transmission like that illustrated, the raceway curvature of race 32a, upon which the torque loading device acts directly, is profiled or given a modified curvature, with reference tothe normal curvature of raceway 26a, as Y shown in Fig. 5. As an example, this view shows at C the center of curvature of the raceway of the driving race 26a in an axial plane, and R the radius of curvature of this raceway. C' indicates the center of curvature of the profiled raceand R' tle radius-of curvature. The difference in curvature of the raceway of race 32a with respect to the raceway of race 26a and the other races istco slight to be apparent in Fig. 1; it is, therefore, exaggerated in Fig. 5. In a double toric transmission mechanism as illustrated in Fig. 1, if the pitch diameter of the circumference including center C be taken as 5.500" the pitch diameter of circumference of. adjusted centerl C should be 5504"; and if the radius R. be taken as 2.500", radius R' should be 2.479". The effect of the modified curvature of the-raceway of race 32a, is to compensate for the differences of elastic detiection in an axial direction of the totality of vthe transmission elements due to different angular positions of the rollers, by maintaining the axial position of the cam carrying race at the radii of contact of the torque loading rollers substantially the same under a given load throughout all ratio changes.

tilted to low gear positions the center C' must be nearer the race axis than the center C of the normal curve and if the yield were the same in both high and lowl gear positions the center C'r would be at the vsame distance from the race axis as the center C of the n ormal curve but displaced slightly toward the profiled race.

.The modification'of the raceway could be made in race 26a instead ofv in race 32a though it `will be appreciated that in that event the position of the center C would be reversed. l

yWe claim:

1. In friction race and roller transmission mechanism, a torque loading device, unyielding abutment means to receive the reaction force thereof, an adjustable gag element arranged to transmit the reaction force of the torque loading device to the abutment means, and means for exerting a continuous yielding force upon the gag element to cause it `to take up and iill the space between the abutment means and torque loading device and thereby maintain the loading device in position to impart the greatest amplitude of axial movement for which it`was designed.

2. In friction race and roller transmission mechanism, a torque loading device composed of relatively adjustable elements, adjusting means, axially unyieldable to the reaction of the torque loading device, arranged to fix the relative positions of said elemen-ts so as to be capable of imparting a greater or lesser amplitude of axial motion, and a' means exerting fa constant yielding force on said adjusting means to cause it to take up `slack in the torque loading device and thereby maintain the elements of the torque loading device in condition to impart the greatest amplitude' of axial movement for which it was designed.

3. In friction race and roller transmission mechanism, a torque loading device comprising axially spaced elements and interposed means for causing axial separation of said elements in response to a relative rotary movement, unyielding abutment means to receive the reaction force thereof, means for adjusting one of said elements axially toward and from the other. consisting of an adjustable gag operatively disposed between.

said axiallyl adjustable element and said abutment means and arranged to bear against said axially adjustable element and means exerting a yielding force on said gag, said gag tending to taire` up and fill thespace betweenthe abutment means and said adjustable element, and saidadjusting means thereby tending to move said axially adjustable element toward its companion.I

4. In friction race and roller' transmission mechanism, a torque loading device comprising cooperating coaxial cam elements capable of relative motion about the axis, one of said cams benut bearing against said axially adjustable cam, and a spring biased toA rotate said nut in a direction to move said axially 'adjustable cam toward its companion.

5. In friction transmission mechanismcomprising coaxial driving and driven races and a coaxial shaft, one of said races having a lost motion driving connection with the shaft, torque loading means comprising cooperating cam elements rotatable respectively with said shaft and' with said race having a lost motion driving coning adjustable axially, a gag comprising a threaded nection with the shaft, means for axially adjust A ing the cam element` driven by the shaft, comprising a nut threaded on the shaft, a spiral spring having one end anchored to the shaft and its other end 'anchored to the nut, and biased to' rotate the nut in a direction to move the cam element drivenn by the shaft toward its companion.

6, Friction race and roller transmission mechafor exerting continuing yielding force upon the gag element to maintain the loading means in position to impart the greatest amplitude of axial movement for which it was designed: a pair oi' coaxial races and interposed power transmitting rollers, said races having opposed toroldal raceways, one oit-said races being directly acted on by- 10 the torque and spring loading means and capable.

nism, including a torque loading and a spring loading means in parallel. a gag element, means of movement toward the other race of the pair and of limited angular movement to render the torque loading means effective; one of said races having a raceway the radius o! which is slightly less than the radius of curvature of the opposed raceway and the center oi' curvature of which is slightly displaced from the center of curvature of said opposed raceway.

WINFIELD D YGOVE. JOHN 

